Greenland's Ice Vanishing Faster Than Previously Thought

A study released just yesterday revealed that "supraglacial" lakes on Greenland have been greatly underestimated, and could trigger future ice loss, so it should come as no surprise then that new related research says this ice sheet is vanishing faster than previously thought.

The Greenland Ice Sheet is the second-largest body of ice on Earth. And, if it melts completely in the face of climate change, it could raise our oceans by a staggering 20 feet, causing extensive damage to coastal areas from Florida to Bangladesh. So with this potential impact, it's surprising that scientists actually know very little about this northern behemoth.

That's why a team from the University of Buffalo set out to paint a more accurate picture of Greenland's ice melt and its contribution to sea level rise.

"The great importance of our data is that for the first time, we have a comprehensive picture of how all of Greenland's glaciers have changed over the past decade," geophysicist Beata Csatho, who led the study, said in a statement.

Using satellite and aerial data from NASA's ICESat (Ice, Cloud and Land Elevation Satellite) spacecraft and Operation IceBridge field campaign, researchers studied nearly 100,000 locations across Greenland from 1993 to 2012. They found that the ice sheet lost about 243 metric gigatons of ice every year from 2003 to 2009. Consequently, an extra 0.68 millimeters of water was added into the oceans annually.

Conventional climate models base their future ice loss predictions on the activity of four well-studied glaciers - Jakobshavn, Helheim, Kangerlussuaq and Petermann. But the new research shows that scientists can't limit themselves to these four glaciers and accurately forecast how the entire ice sheet will dump ice into the oceans.

"There are 242 outlet glaciers wider than 1.5 km on the Greenland Ice Sheet, and what we see is that their behavior is complex in space and time," Csatho explained. "The local climate and geological conditions, the local hydrology - all of these factors have an effect. The current models do not address this complexity."

According to the study, published in the journal Proceedings of the National Academy of Sciences, there isn't a one-size-fits-all model for Greenland's glaciers. Some thickened when the temperature rose, some thinned, and some displayed both thinning and thickening. Researchers plan to continue investigating why glaciers respond differently to warming to improve upon climate models.

By focusing on factors involved in ice melt that earlier studies neglected to consider, Csatho and her team believe that the Greenland Ice Sheet could lose ice faster in the future than previously suggested.

"These studies represent new leaps in our knowledge of how the ice sheet is losing ice. It turns out the ice sheet is a lot more complex than we ever thought," Tom Wagner, program scientist for NASA's cryosphere program in Washington, said in a statement.

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